1. Field of the Invention
The present invention generally relates to a pivot unit, and more particularly relates to a drop away leaf pivot unit for use with a clamp in a manufacturing assembly line.
2. Description of Related Art
Pivot units have been known for numerous years in the manufacturing assembly line industries. Generally, pivot units are used to pivot a clamp, holding device, tool, or other unit that is performing an operation on a product along an assembly line. The pivot unit generally will pivot the tool or clamp to a predetermined position along the manufacturing line and either hold or perform an operation on a work piece or a product along the assembly line process. Generally, the pivot action is in a circular arc and is performed such that during non-operation of that device the pivot unit will move the clamp or tool into a neutral position away from the manufacturing assembly line. Pivot units also may be used to pivot into position a clamp that will hold a work piece in a proper position along the work line for a specific workstation in the manufacturing assembly line, such as those found in an automotive assembly line.
Many of the prior art pivot units are open architecture and are vulnerable to the contaminates in the operating environment of the manufacturing process. In particular many manufacturing assembly processes include a plurality of welding robots and welding arms used to connect or place pieces into predetermined positions. Many of the robotic arms have weld units at the end thereof and perform welding operations on frames or other units, etc. in the manufacturing environment. When the weld is being placed by the robotic arm unit at the end of the pivot unit weld slag and other materials which are used to prepare the metal and provide for a proper weld is splattered and dropped at various positions along the line and even into the pivot units. This weld slag damages and reduces the operational efficiency and durability of the prior art pivot units in the current manufacturing environments. Furthermore, the prior art pivot units are bulky with complicated designs that include a plurality of rotating pneumatically operated parts designed to move only one part or tool in one predetermined arc along a manufacturing line. Therefore, the prior art pivot units have no flexibility and were designed specifically for one part at one predetermined position along a manufacturing assembly line. Therefore, the costs to design, install and repair are great for these prior art pivot units. Furthermore, the use of the prior art open architecture increases the cost to manufacturers by reducing the durability and reliability of the pivot units because of possible contamination by weld slag and other contaminates found in a robotic manufacturing assembly line. Furthermore, if a design change has to be made to the work piece being built on the manufacturing line a completely new open architecture pivot unit would have to be built thus increasing the costs to the manufacturer. Furthermore, significant design changes would have to be made and numerous parts replaced to retrofit an existing pivot unit having a predetermined stand alone architecture to accommodate any new changes to the assembly line or the work piece being manufactured along the assembly line.
Therefore, there is a need in the art for a new and improved pivot unit that is enclosed such that weld slag and other contaminates of the manufacturing environment will not effect the durability or reliability of the pivot unit. Furthermore, there is a need in the art for a pivot unit that is capable of being adjustable to accommodate various manufacturing lines and pieces or products without having to rebuild a complete unit. Furthermore, there is a need in the art for a low cost pivot unit that is more robust, reliable and easily modified to accommodate numerous changes in a manufacturing environment with a short down time for the manufacturing line.